1. Field
The exemplary embodiments relate to a substrate transport apparatus and, more particularly, to a robot transport arm of a substrate transport apparatus.
2. Brief Description of Related Developments
Various types of substrate transport apparatus are known in the art. Examples of substrate transport apparatus are described in U.S. Pat. Nos. 5,404,894, 5,431,529 and 5,765,983. U.S. Pat. No. 4,951,601 discloses a substrate processing apparatus with multiple processing chambers and a substrate transport apparatus.
In many substrate processing applications, a substrate transport apparatus includes a substrate transport robot which is mounted in a central transfer chamber. Typically, the transport robot has a controller that controls a drive that powers an arm assembly. The arm assembly typically operates in the transfer chamber to transfer a substrate to and from various processing chambers on a substrate support or an end effector.
Generally, the transport and processing chambers are maintained substantially at a vacuum to prevent contamination of substrates while being transported and processed. Other atmospheres may also be maintained in the transport and processing chambers if required. Some processing techniques may require the use of atmospheres that are corrosive, have an elevated temperature, or that generally present a hostile environment to the transport robot electronics and drive. In these cases, it would be advantageous to locate the controller and drive outside the hostile environment of the transfer chamber. It would also be advantageous to simplify the mechanical coupling between the drive and the end effector. It would be still further advantageous to couple the drive to the end effector in a manner that does not require a mechanical connection through the wall of the transfer chamber.